Polarizing plate with optical compensation layer and organic EL panel using same

ABSTRACT

There is provided a polarizing plate with optical compensation layers having the following features: the polarizing plate is excellent in antireflection characteristic in an oblique direction while maintaining an excellent antireflection characteristic in a front direction; the polarizing plate can achieve such excellent antireflection characteristics over a wide wavelength band; and the polarizing plate has a neutral hue in the oblique direction. A polarizing plate with optical compensation layers according to the present invention is used for an organic EL panel. The polarizing plate with optical compensation layers includes: a polarizer; a first optical compensation layer; a second optical compensation layer; and a third optical compensation layer. Each of the first optical compensation layer, the second optical compensation layer, and the third optical compensation layer shows a refractive index characteristic of nx&gt;nz&gt;ny.

TECHNICAL FIELD

The present invent ion relates to a polarizing plate with opticalcompensation layers and an organic EL panel using the same.

BACKGROUND ART

In recent years, along with widespread use of thin displays, a displayhaving an organic EL panel mounted thereon (organic EL displayapparatus) has been proposed. The organic EL panel has a metal layerhaving high reflectivity, and hence is liable to cause a problem of, forexample, reflection of ambient light or reflection of a background. Inview of the foregoing, it has been known that such problem is preventedby arranging a circularly polarizing plate on a viewer side. Acircularly polarizing plate in which a retardation film (typically a λ/4plate) is laminated so that its slow axis may form an angle of about 45°with regard to the absorption axis of a polarizer has been known as ageneral circularly polarizing plate. In addition, an attempt has beenmade to laminate retardation films (optical compensation layers) havingvarious optical characteristics for further improving an antireflectioncharacteristic of the circularly polarizing plate. However, conventionalcircularly polarizing plates each involve a problem in that areflectance in an oblique direction is large (i.e., an antireflectioncharacteristic in the oblique direction is insufficient). In addition,the conventional circularly polarizing plates each involve a problem, inthat a wavelength band in which a satisfactory antireflectioncharacteristic is obtained is narrow. Further, the conventionalcircularly polarizing plates each involve a problem in that a hue in theoblique direction undergoes undesired coloring.

CITATION LIST Patent Literature

[PTL 1] JP 3325560 B2

SUMMARY OF INVENTION Technical Problem

The present invention has been made to solve the above-mentionedconventional problems, and a primary object of the present invention isto provide a polarizing plate with optical compensation layers havingthe following features: the polarizing plate is excellent inantireflection characteristic in an oblique direction while maintainingan excellent antireflection characteristic in a front direction; thepolarizing plate can achieve such excellent antireflectioncharacteristics over a wide wavelength band; and the polarizing platehas a neutral hue in the oblique direction.

Solution to Problem

A polarizing plate with optical compensation layers according to anembodiment of the present invention includes: a polarizer; a firstoptical compensation layer; a second optical compensation layer; and athird optical compensation layer. Each of the first optical compensationlayer, the second optical compensation layer, and the third opticalcompensation layer shows a refractive index characteristic of nx>nz>ny.The polarizing plate with optical compensation layers is used for anorganic EL panel.

In one embodiment of the present invention, each of the first opticalcompensation layer, the second optical compensation layer, and the thirdoptical compensation layer satisfies a relationship of Re(450)≥Re(550)where Re(450) and Re(550) represent in-plane retardations measured at23° C. with light having a wavelength of 450 nm and light having awavelength of 550 nm, respectively.

In one embodiment of the present invention, the first opticalcompensation layer has an Re(550) of from 230 nm to 310 nm and an Nzcoefficient of from 0.1 to 0.4, and an absorption axis of the polarizerand a slow axis of the first optical compensation layer aresubstantially perpendicular to each other.

In one embodiment of the present invention, the second opticalcompensation layer has an Re(550) of from 210 nm to 270 nm and an Nzcoefficient of from 0.3 to 0.7, and an angle formed by an absorptionaxis of the polarizer and a slow axis of the second optical compensationlayer is from 5° to 25°, from 65° to 85°, from 95° to 115°, or from 155°to 175°.

In one embodiment of the present invention, the third opticalcompensation layer has an Re(550) of from 80 nm to 160nm and an Nzcoefficient of from 0.3 to 0.7, and an angle formed by an absorptionaxis of the polarizer and a slow axis of the third optical compensationlayer is from 5° to 25°, from 65° to 85°, from 95° to 115°, or from 155°to 175°.

According to another aspect of the present invention, there is providedan organic EL panel. The organic EL panel includes the polarizing platewith optical compensation layers as described above.

Advantageous Effects of Invention

According to the present invention, the three optical compensationlayers each showing a refractive index characteristic of nx>nz>ny areused in the polarizing plate with optical compensation layers.Accordingly, the polarizing plate with optical compensation layershaving the following features can be obtained: the polarizing plate isexcellent in antireflection characteristic in an oblique direction whilemaintaining an excellent antireflection characteristic in a frontdirection; the polarizing plate can achieve such excellentantireflection characteristics over a wide wavelength band; and thepolarizing plate has a neutral hue in the oblique direction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view of a polarizing plate with opticalcompensation layers according to one embodiment of the presentinvention.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention are described below.However, the present invention is not limited to these embodiments.

Definitions of Terms and Symbols

The definitions of terms and symbols used herein are as described below.

(1) Refractive Indices (nx, ny, and nz)

“nx” represents a refractive index in a direction in which an in-planerefractive index is maximum (that is, slow axis direction), “ny”represents a refractive index in a direction perpendicular to the slowaxis in the plane (that is, fast axis direction), and “nz” represents arefractive index in a thickness direction.

(2) In-Plane Retardation (Re)

“Re(λ)” refers to an in-plane retardation measured at 23° C. with lighthaving a wavelength of λ nm. The Re(λ) is determined from the equation“Re=(nx−ny)×d” when the thickness of a layer (film) is represented by d(nm). For example, “Re(550)” refers to an in-plane retardation measuredat 23° C. with light having a wavelength of 550 nm.

(3) Thickness Direction Retardation (Rth)

“Rth (λ)” refers to a thickness direction retardation measured at 23° C.with light having a wavelength of λ nm. The Rth(λ) is determined fromthe equation “Rth=(nx−nz)×d” when the thickness of a layer (film) isrepresented by d (nm). For example, “Rth(550)” refers to a thicknessdirection retardation measured at 23° C. with light having a wavelengthof 550 nm.

(4) Nz Coefficient

An Nz coefficient is determined from the equation “Nz=Rth/Re”.

(5) Substantially Perpendicular or Parallel

The expressions “substantially perpendicular” and “approximatelyperpendicular” include a case in which an angle formed by two directionsis 90°±10°, and the angle is preferably 90°±7°, more preferably 90°±5°.The expressions “substantially parallel” and “approximately parallel”include a case in which an angle formed by two directions is 0±10°, andthe angle is preferably 0°±7°, more preferably 0°±5°. Moreover, thesimple expression “perpendicular” or “parallel” as used herein mayinclude a substantially perpendicular state or a substantially parallelstate.

A. Overall Configuration of Polarizing Plate with Optical CompensationLayers

FIG. 1 is a schematic sectional view of a polarizing plate with opticalcompensation layers according to one embodiment of the presentinvention. A polarizing plate 100 with optical compensation layersaccording to this embodiment includes a polarizer 10, a first opticalcompensation layer 30, a second optical compensation layer 40, and athird optical compensation layer 50. In practical use, a protectivelayer 20 may be arranged on the side of the polarizer 10 opposite to thefirst optical compensation layer 30 like the illustrated example. Inaddition, the polarizing plate with optical compensation layers mayinclude another protective layer (also referred to as “inner protectivelayer” ) between the polarizer 10 and the first optical compensationlayer 30. In the illustrated example, the inner protective layer isomitted. In this case, the first optical compensation layer 30 may alsofunction as an inner protective layer. With such configuration, furtherthinning of the polarizing plate with optical compensation layers can beachieved. Further, a conductive layer and a substrate (none of which isshown) may toe arranged on the side of the third optical compensationlayer 50 opposite to the second optical compensation layer 40 (i.e.,outside the third, optical compensation, layer 50) in the stated orderas required. The substrate is laminated so as to be in close contactwith the conductive layer. The phrase “laminated so as to be in closecontact” as used herein means that two layers are laminated directly andfixedly without an adhesion layer (e.g., an adhesive layer or apressure-sensitive adhesive layer) being interposed. The conductivelayer and the substrate may be typically introduced as a laminate of thesubstrate and the conductive layer into the polarizing plate 100 withoptical compensation layers. When the conductive layer and the substrateare further arranged, the polarizing plate 100 with optical compensationlayers can be suitably used for an inner touch panel-type input displayapparatus.

In the embodiment of the present invention, each of the first opticalcompensation layer 30, the second optical compensation layer 40, and thethird optical compensation layer 50 shows a refractive indexcharacteristic of nx>nz>ny. When the three optical compensation layerseach showing a refractive index characteristic of nx>nz>ny are used,light leakage or the like due to an apparent axis shift of theabsorption axis of the polarizer when viewed from an oblique directionis prevented while an excellent antireflection characteristic of thepolarizing plate with optical compensation layers in a front directionby virtue of an excellent circular polarization function thereof ismaintained. Accordingly, an excellent antireflection characteristic canbe achieved, in the oblique direction. Further, such excellentantireflection characteristics can be achieved over a wide wavelengthband, and a hue that is neutral (i.e., free of undesired coloring) canbe achieved in the oblique direction.

Each of the first optical compensation layer 30, the second opticalcompensation layer 40, and the third optical compensation layer 50typically shows such a positive wavelength dispersion characteristicthat its retardation value reduces in accordance with an increase inwavelength of measurement light, or such a flat wavelength dispersioncharacteristic that the retardation value hardly changes even when thewavelength of the measurement light changes. Such configuration has anadvantage in that the respective optical compensation layers can beformed of the same material. More specifically, each of the firstoptical compensation layer 30, the second optical compensation layer 40,and the third optical compensation layer 50 preferably satisfies arelationship of Re(450)≥Re(550), and more preferably further satisfies arelationship of Re(550)≥Re(650). It is more preferred that the firstoptical compensation layer 30, the second optical compensation layer 40,and the third optical compensation layer 50 show the same wavelengthdispersion characteristic. When, the three optical, compensation layershave the same wavelength dispersion characteristic, it becomes easier toselect a material for the respective optical compensation layers.

The first optical compensation layer 30 preferably has an in-planeretardation Re(550) of from 230 nm to 310 nm. In one embodiment, the Nzcoefficient of the first, optical compensation layer is preferably from0.1 to 0.4. In this ease, it is preferred that the slow axis of thefirst optical, compensation layer 30 and the absorption axis of thepolarizer 10 be substantially perpendicular to each other. In anotherembodiment, the Nz coefficient of the first optical compensation layeris preferably from 0.6 to 0.9. In this case, it is preferred that, theslow axis of the first, optical compensation layer 30 and the absorptionaxis of the polarizer 10 be substantially parallel to each other.

In one embodiment, the second optical compensation layer 40 preferablyhas an in-plane retardation Re(550) of from 210 nm to 270 nm, andpreferably has an Nz coefficient of from 0.3 to 0.7. In one embodiment,the third optical compensation layer 50 preferably has an in-planeretardation Re(550) of from 80 nm to 160 nm, and preferably has an Nzcoefficient of from 0.3 to 0.7.

In one embodiment, an angle formed by the slow axis of the secondoptical, compensation, layer 40 and the absorption axis of the polarizer10 is preferably from 65° to 85°, or from 155°to 175°. In this case, anangle formed by the slow axis of the third, optical compensation layer50 and the absorption axis of the polarizer 10 is preferably from 5° to25°, or from 95° to 115°. In another embodiment, an angle formed by theslow axis of the second optical compensation layer 40 and the absorptionaxis of the polarizer 10 is preferably from 5° to 25°, or from 95° to115°. In this case, an angle formed by the slow axis of the thirdoptical compensation layer 50 and the absorption axis of the polarizer10 is preferably from 65° to 85°, or from 155° to 175°.

In the case where each of the first optical compensation layer to thethird optical compensation layer has such in-plane retardation and Nzcoefficient as described above, particularly preferred slow axisdirections of the respective optical compensation layers when theabsorption axis direction of the polarizer is defined as 0° are asfollows: polarizer (0°)/first optical compensation layer (90°)/secondoptical compensation layer (75°)/third optical compensation layer (15°);polarizer (0°)/first optical compensation layer (90°)/second opticalcompensation layer (15°)/third optical compensation layer (75°);polarizer (0°)/first optical compensation layer (90°)/second opticalcompensation layer (165°)/third optical compensation layer (105°); orpolarizer (0°)/first optical compensation layer (90°)/second opticalcompensation layer (105°)/third optical compensation layer (165°).

In the illustrated example, the first optical compensation layer 30, thesecond, optical compensation layer 40, and the third opticalcompensation layer 50 are arranged in the stated order from thepolarizer 10 side.

Each layer and each optical film forming the polarizing plate withoptical compensation layers are described in detail below.

A-1. Polarizer

Any appropriate polarizer may foe adopted as the polarizer 10. Forexample, a resin film forming the polarizer may be a single-layer resinfilm, or may foe a laminate of two or more layers.

Specific examples of the polarizer including a single-layer resin filminclude: a polarizer obtained by subjecting a hydrophilic polymer film,such as a polyvinyl alcohol (PVA)-based film, a partially formalizedPVA-based film, or an ethylene-vinyl acetate copolymer-based partiallysaponified film, to dyeing treatment with a dichroic substance, such asiodine or a dichroic dye, and stretching treatment; and a polyene-basedalignment film, such as a dehydration-treated product of PVA or adehydrochlorination-treated product of polyvinyl chloride. A polarizerobtained by dyeing the PVA-based film with iodine and uniaxiallystretching the resultant is preferably used because the polarizer isexcellent in optical characteristics.

The dyeing with iodine is performed by, for example, immersing thePVA-based film in an aqueous solution of iodine. The stretching ratio ofthe uniaxial stretching is preferably from 3 times to 7 times. Thestretching may be performed after the dyeing treatment, or may beperformed while the dyeing is performed. In addition, the dyeing may beperformed after the stretching has been performed. The PVA-based film issubjected to swelling treatment, cross-linking treatment, washingtreatment, drying treatment, or the like as required. For example, whenthe PVA-based film is immersed in water to be washed with water beforethe dyeing, contamination or an antiblocking agent on the surface of thePVA-based film can be washed off. In addition, the PVA-based film isswollen and hence dyeing unevenness or the like can be prevented.

The polarizer obtained by using the laminate is specifically, forexample, a polarizer obtained by using a laminate of a resin substrateand a PVA-based resin layer (PVA-based resin film) laminated on theresin substrate, or a laminate of a resin substrate and a PVA-basedresin layer formed on the resin substrate through application. Thepolarizer obtained by using the laminate of the resin substrate and thePVA-based resin layer formed on the resin substrate through applicationmay be produced by, for example, a method involving: applying aPVA-based resin solution onto the resin substrate; drying the solutionto form the PVA-based resin layer on the resin substrate, therebyproviding the laminate of the resin substrate and the PVA-based resinlayer; and stretching and dyeing the laminate to turn the PVA-basedresin layer into the polarizer. In this embodiment, the stretchingtypically includes the stretching of the laminate under a state in whichthe laminate is immersed in an aqueous solution of boric acid. Thestretching may further include the in-air stretching of the laminate athigh temperature (e.g., 95° C. or more) before the stretching in theaqueous solution of boric acid as required. The resultant laminate ofthe resin substrate and the polarizer may be used as it is (i.e., theresin substrate maybe used as a protective layer for the polarizer).Alternatively, a product obtained as described below may be used: theresin substrate is peeled from the laminate of the resin substrate andthe polarizer, and any appropriate protective layer in accordance withpurposes is laminated on the peeling surface. The details of such methodof producing a polarizer are described in, for example, JP 2012-73580 A,the description of which is incorporated herein by reference in itsentirety.

The thickness of the polarizer is preferably 25 μm or less, morepreferably from 1 μm to 12 μm, still more preferably from 3 μm to 12 μm,particularly preferably from 3 μm to 8 μm. When the thickness of thepolarizer falls within such range, curling at the time of heating can besatisfactorily suppressed, and satisfactory appearance durability at thetime of heating is obtained.

The polarizer preferably shows absorption dichroism at any wavelength inthe wavelength range of from 380 nm to 780 nm. The single layertransmittance of the polarizer is preferably from 42.0% to 46.0%, morepreferably from 44.5% to 46.0%. The polarization degree of the polarizeris preferably 97.0% or more, more preferably 99.0% or more, still morepreferably 99.9% or more.

A-2. First Optical Compensation Layer

As described above, the refractive index characteristic of the firstoptical compensation layer 30 shows a relationship of nx>nz>ny. Thein-plane retardation Re(550) of the first, optical compensation layer ispreferably from 230 nm to 310 nm, more preferably from 240 nm to 300 nm,still more preferably from 260 nm to 280 nm. When the in-planeretardation of the first optical compensation layer falls within suchrange, a reduction in antireflection function of the polarizing platewith optical compensation layers in the oblique direction resulting fromthe apparent axis shift of the absorption axis of the polarizer can beprevented by making the slow axis of the first optical compensationlayer substantially perpendicular to the absorption axis of thepolarizer.

In one embodiment, the Nz coefficient of the first optical compensationlayer is preferably from 0.1 to 0.4, more preferably from 0.2 to 0.3,still more preferably from 0.23 to 0.27. When the Nz coefficient fallswithin such range, in combination with the effect of the in-planeretardation, a more excellent antireflection characteristic in theoblique direction can be achieved by making the slow axis of the firstoptical compensation layer and the absorption axis of the polarizersubstantially perpendicular to each other. In another embodiment, the Nzcoefficient of the first optical compensation layer is preferably from0.6 to 0.9, more preferably from 0.7 to 0.3, still more preferably from0.73 to 0.77. When the Nz coefficient falls within such range, the sameeffect can be achieved by making the slow axis of the first opticalcompensation layer and the absorption axis of the polarizersubstantially parallel to each other.

As described above, the first optical compensation layer preferablyshows such a positive wavelength dispersion characteristic that itsretardation value reduces in accordance with an increase in wavelengthof measurement light, or such a flat wavelength dispersioncharacteristic that the retardation value hardly changes even when thewavelength of the measurement light changes. When the first opticalcompensation layer shows any such wave length dispersion characteristic,the widening of the wavelength band can be achieved by a laminatedconfiguration with any other optical compensation layer. Specifically,the first optical compensation layer preferably satisfies a relationshipof Re(450)≥Re(550). A ratio “Re(450)/Re(550)” is preferably from 1.00 to1.20, more preferably from 1.00 to 1.15. Further, the first opticalcompensation layer preferably satisfies a relationship ofRe(550)≥Re(650). A ratio “Re(550)/Re(650)” is preferably from 1.00 to1.11, more preferably from 1.00 to 1.08.

The first optical compensation layer is typically a retardation filmformed of any appropriate resin that can achieve the above-mentionedcharacteristic. Examples of the resin forming the retardation filminclude polyarylate, polyamide, polyimide, polyester,polyaryletherketone, polyamide-imide, polyesterimide, polyvinyl alcohol,polyfumarate, polyethersulfone, polysulfone, a norbornene resin, apolycarbonate resin, a cellulose resin, and polyurethane. Those resinsmay be used alone or in combination thereof. Of those, polyarylate or apolycarbonate resin is preferred, and a polycarbonate resin orpolyarylate represented by the following formula (I) is more preferred.

In the formula (I): A and B each represent a substituent, specifically ahalogen atom, an alkyl group having 1, to 6 carbon atoms, or asubstituted or unsubstituted aryl group, and A and B may be identical toor different from each other; a and b represent the numbers ofsubstitutions with A and B, respectively, and each represent an integerof from 1 to4 represents a covalent bond, a CH₂ group, a C(CH₃)₂ group,a C(CZ₃)₂ group where Z represents a halogen atom, a CO group, an Oatom, a S atom, a SO₂ group, a Si(CH₂CH₃)₂ group, or a N(CH₃) group; R1represents a linear or branched alkyl group having 1 to 10 carbon atoms,or a substituted or unsubstituted aryl group; R2 represents a linear orbranched alkyl group having 2 to 10 carbon atoms, or a substituted orunsubstituted aryl group; R3, R4, R5, and R6 each independentlyrepresent a hydrogen atom or a linear or branched alkyl group having 1to 4 carbon atoms, and R3, R4, R5, and R6 may be identical to ordifferent from each other; and p1 represents an integer of from 0 to 3,p2 represents an integer of from 1 to 3, and n represents an integer of2 or more.

The first optical compensation layer may be formed by, for example,dissolving or dispersing the resin in any appropriate solvent to preparean application liquid, applying the application liquid to a shrinkablefilm to form an applied film, and shrinking the applied film. Typically,the shrinkage of the applied film is performed as follows: a laminate ofthe shrinkable film and the applied film is heated to shrink theshrinkable film, and the applied film is shrunk by such shrinkage of theshrinkable film. The shrinkage ratio of the applied, film is preferablyfrom 0.50 to 0.99, more preferably from 0.60 to 0.98, still morepreferably from 0.70 to 0.95. A heating temperature is preferably from130° C. to 170° C., more preferably from 150° C. to 160° C. In oneembodiment, at the time of the shrinkage of the applied film, thelaminate may foe stretched in a direction perpendicular to the directionin which the applied film is shrunk. In this case, the stretching ratioof the laminate is preferably from 1.01 times to 3.0 times, morepreferably from 1.05 times to 2.0 times, still more preferably from 1.10times to 1.50 times. Specific examples of a material forming theshrinkable film include polyolefin, polyester, an acrylic resin,polyamide, polycarbonate, a norbornene resin, polystyrene, polyvinylchloride, polyvinylidene chloride, a cellulose resin, polyethersulfone,polysulfone, polyimide, polyacryl, an acetate resin, polyarylate,polyvinyl alcohol, and a liquid crystal polymer. Those materials may beused alone or in combination thereof. The shrinkable film is preferablya stretched film formed from any such material. Alternatively, the firstoptical compensation layer may be formed by bonding the shrinkable filmto one surface, or each of both surfaces, of a film formed of the resinwith, for example, an acrylic pressure-sensitive adhesive, and thenheating the resultant laminate to shrink the laminate.

The thickness of the first optical compensation layer is preferably from10 to 150 μm, more preferably from 10 μm to 50 μm, still more preferablyfrom 10 μm to 30 μm. With such thickness, the desired in-planeretardation and the desired Nz coefficient can be obtained.

A-3. Second Optical Compensation Layer

As described above, the refractive index characteristic of the secondoptical, compensation layer 40 shows a relationship of nx>nz>ny. In oneembodiment, as described above, the angle formed by the slow axis of thesecond optical compensation layer 40 and the absorption axis of thepolarizer 10 is preferably from 65° to 85°, more preferably from 70° to80°, still more preferably from 73° to 77°, particularly preferablyabout 75°. In another example of this embodiment, as described above,the angle is preferably from 155° to 175°, more preferably from 160° to170°, still more preferably from 163° to 167°, particularly preferablyabout 165°. In another embodiment, as described above, the angle formedby the slow axis of the second optical compensation layer 40 and theabsorption axis of the polarizer 10 is preferably from 5° to 25°, morepreferably from 10° to 20°, still more preferably from 13°to 17°,particularly preferably about 15°. In another example of thisembodiment, as described above, the angle is preferably from 95° to115°, more preferably from 100° to 110°, still more preferably from 103°to 107°, particularly preferably about 105°. When the angle is setwithin such range, a more excellent antireflection characteristic in theoblique direction can be achieved by a synergistic effect with effectsexhibited by the in-plane retardation and Nz coefficient of the secondoptical compensation layer.

The in-plane retardation Re(550) of the second optical compensationlayer is preferably from 210 nm to 270 nm, more preferably from 220 nmto 260 nm, still more preferably from 230 nm to 250 nm. In the casewhere the in-plane retardation, of the second optical, compensationlayer is set to be smaller than that of a so-called λ/2 plate, thereflection hue of the polarizing plate with optical compensation layerscan be neutralized even when a material showing a positive wavelengthdispersion characteristic is used.

The Nz coefficient of the second optical compensation layer ispreferably from 0.3 to 0.7, more preferably from 0.4 to 0.6, still morepreferably from 0.45 to 0.55, particularly preferably about 0.5. Whenthe Nz coefficient of the second optical compensation layer falls withinsuch range, in combination with the effect of the in-plane retardation,a more excellent antireflection characteristic in the oblique directioncan be achieved by setting the angle formed by the slow axis of thesecond optical compensation layer and the absorption axis of thepolarizer to, for example, from 65° to 85° (in particular, around 75°),or from 155° to 175° (in particular, around 165°) as described above.

As described above, the second optical compensation layer preferablyshows such a positive wavelength dispersion characteristic that itsretardation value reduces in accordance with an increase in wavelengthof measurement light, or such a flat wavelength dispersioncharacteristic that the retardation value hardly changes even when thewavelength of the measurement light changes. When the second opticalcompensation layer shows any such wave length dispersion characteristic,the widening of the wavelength band can be achieved by a laminatedconfiguration with any other optical compensation layer. Specifically,the second optical compensation layer preferably satisfies arelationship of Re(450)≥Re(550). A ratio “Re(450)/Re(550)” is preferablyfrom 1.00 to 1.20, more preferably from 1.00 to 1.15. Further, thesecond optical compensation layer preferably satisfies a relationship ofRe(550)≥Re(650). A ratio “Re(550)/Re(650)” is preferably from 1.00 to1.11, more preferably from 1.00 to 1.08.

The thickness of the second optical compensation layer is preferablyfrom 10 μm to 150 μm, more preferably from 10 μm to 50 μm, still morepreferably from 10 μm to 30 μm. With such thickness, the desiredin-plane retardation and the desired Nz coefficient can be obtained.

A constituent material for the second optical compensation layer and amethod of forming the layer are as described in the section A-2 for thefirst optical compensation layer.

A-4. Third .Optical Compensation Layer

As described above, the refractive index characteristic of the thirdoptical compensation layer 50 shows a relationship of nx>nz>ny. In oneembodiment, as described above, the angle formed by the slow axis of thethird optical compensation layer 50 and the absorption axis of thepolarizer 10 is preferably from 5° to 25°, more preferably from 10° to20°, still more preferably from 13° to 17°, particularly preferablyabout 15°. In another example of this embodiment, as described above,the angle is preferably from 95° to 115°, more preferably from 100° to110°, still more preferably from 103° to 107°, particularly preferablyabout 105°. In another embodiment, as described above, the angle formedby the slow axis of the third optical compensation layer 50 and theabsorption axis of the polarizer 10 is preferably from 65° to 85°, morepreferably from 70° to 80°, still more preferably from 73° to 77°,particularly preferably about 75°. In another example of thisembodiment, as described above, the angle is preferably from 155° to175°, more preferably from 160° to 170°, still more preferably from 163°to 167°, particularly preferably about 165°. Mien the angle is setwithin such range, a more excellent antireflection characteristic in theoblique direction can be achieved by a synergistic effect with effectsexhibited by the in-plane retardation and Nz coefficient of the thirdoptical compensation layer.

The in-plane retardation Re(550) of the third optical compensation layeris preferably from 80 nm to 160 nm, more preferably from 100 nm to 140nm, still more preferably from 110 nm to 130 nm. In the case where thein-plane retardation of the third optical compensation layer is set tobe smaller than that of a so-called λ/4 plate, the reflection hue of thepolarizing plate with optical compensation layers can be neutralizedeven when a material showing a positive wavelength dispersioncharacteristic is used.

The Nz coefficient of the third optical compensation layer is preferablyfrom 0.3 to 0.7, more preferably from 0.4 to 0.6, still more preferablyfrom 0.45 to 0.55, particularly preferably about 0.5. When the Nzcoefficient of the third optical compensation layer falls within suchrange, in combination with the effect of the in-plane retardation, amore excellent antireflection characteristic in the oblique directioncan be achieved by setting the angle formed by the slow axis of thethird optical compensation layer and the absorption axis of thepolarizer to from 5° to 25° (in particular, around 10°), or from 95° to115° (in particular, around 100°) as described above.

As described above, the third optical compensation layer preferablyshows such a positive wavelength dispersion characteristic that itsretardation value reduces in accordance with an increase in wavelengthof measurement light, or such a flat wavelength dispersioncharacteristic that the retardation value hardly changes even when thewavelength of the measurement light changes. When the third opticalcompensation layer shows any such wavelength dispersion characteristic,the widening of the wavelength band can foe achieved by a laminatedconfiguration with any other optical compensation layer. Specifically,the third optical compensation layer preferably satisfies a relationshipof Re(450)≥Re(550). A ratio “Re(450)/Re(550)” is preferably from 1.00 to1.20, more preferably from 1.00 to 1.15. Further, the third opticalcompensation layer preferably satisfies a relationship ofRe(550)≥Re(650). A ratio “Re(550)/Re(650)” is preferably from 1.00 to1.11, more preferably from 1.00 to 1.08.

The thickness of the third optical compensation layer is preferably from5 μm to 150 μm, more preferably from 5 μm to 50 μm, still morepreferably from 5 μm to 30 μm. With such thickness, the desired in-planeretardation and the desired Nz coefficient can be obtained.

A constituent material for the third optical compensation layer and amethod of forming the layer are as described in the section A-2 for thefirst optical compensation layer.

A-5. Protective Layer

The protective layer 20 is formed of any appropriate film that may beused as a protective layer for a polarizer. A material serving as a maincomponent of the film is specifically, for example: a cellulose-basedresin, such as triacetylcellulose (TAG); a transparent resin, such as apolyester-based, polyvinyl alcohol-based, polycarbonate-based,polyamide-based, polyimide-based, polyethersulfone-based,polysulfone-based, polystyrene-based, polynorbornene-based,polyolefin-based, (meth)acrylic, or acetate-based transparent resin; ora thermosetting resin or a UV-curable resin, such as a (meth) acrylic,urethane-based, (meth)acrylic urethane-based, epoxy-based, orsilicone-based thermosetting resin or UV-curable resin. A furtherexample thereof is a glassy polymer, such as a siloxane-based polymer.In addition, a polymer film described in JP 2001- 343529 A (WO 01/37007A1) may be used. For example, a resin composition containing athermoplastic resin having a substituted or unsubstituted imide group ona side chain thereof, and a thermoplastic resin having a substituted orunsubstituted phenyl group and a nitrile group on side chains thereofmay be used as the material for the film, and the composition is, forexample, a resin composition containing an alternating copolymer formedof isobutene and N-methylmaleimide, and an acrylonitrile-styrenecopolymer. The polymer film may be, for example, an extrudate of theresin composition.

The protective layer 20 may be subjected to surface treatment, such ashard coat treatment, antireflection treatment, anti-sticking treatment,or antiglare treatment, as required. Further/alternatively, theprotective layer 20 may be subjected to treatment for improvingviewability when the display screen of an image display apparatus isviewed through polarized sunglasses (typically the impartment of acircular (elliptical) polarization function or the impartment of anultra-high retardation) as required. When any such treatment isperformed, even in the case where the display screen is viewed through apolarizing lens, such as polarized sunglasses, excellent viewability canbe achieved. Therefore, the polarizing plate with optical compensationlayers is suitably applicable even to an image display apparatus thatmay be used outdoors.

The thickness of the protective layer 20 is typically 5 mm or less,preferably 1 mm or less, more preferably from 1 μm to 500 μm, still morepreferably from 5 μm to 150 μm. When the protective layer is subjectedto surface treatment, its thickness is a thickness including thethickness of a surf ace-treated layer.

When an inner protective layer is arranged between the polarizer 10 andthe first optical compensation layer 30, it is preferred that the innerprotective layer be optically isotropic. The phrase “opticallyisotropic” as used herein means that the layer has an in-planeretardation Re(550) of from 0 nm to 10 nm and a thickness directionretardation Rth(550) of from −10 nm to +10 nm. The inner protectivelayer may be composed of any appropriate material as long as the layeris optically isotropic. The material may be appropriately selected from,for example, the materials described above for the protective layer 20.

The thickness of the inner protective layer is preferably from 5 μm to200 μm, more preferably from 10 μm to 100 μm, still more preferably from15 μm to 95 μm.

A-6 . Conductive Layer or Conductive Layer with Substrate

The conductive layer may be formed by forming a metallic oxide film onany appropriate substrate through any appropriate film forming method(e.g., a vacuum vapor deposition method, a sputtering method, a CVDmethod, an ion plating method, and a spraying method). After the filmformation, heating treatment (e.g., at from 100° C. to 200° C.) may beperformed as required. Mien the heating treatment is performed, anamorphous film can foe crystallized. Examples of the metal oxide includeindium oxide, tin oxide, zinc oxide, indium-tin composite oxide,tin-antimony composite oxide, zinc-aluminum composite oxide, andindium-zinc composite oxide. An indium oxide may be doped with adivalent metal ion or a tetravalent metal ion. The metal oxide ispreferably an indium-based composite oxide, more preferably indium-tincomposite oxide (ITO). The indium-based composite oxide has features ofhaving a high transmittance (e.g., 80% or more) in a visible lightregion (380 nm to 780 nm) and having a low surface resistance value perunit area.

When the conductive layer contains the metal oxide, the thickness Of theconductive layer is preferably 50 nm or less, more preferably 35 nm orless. The lower limit of the thickness of the conductive layer ispreferably 10 nm.

The surface resistance value of the conductive layer is preferably 300ohms per square (Ω/□) or less, more preferably 150 Ω/□ or less, stillmore preferably 100 Ω/□ or less.

The conductive layer may be transferred from the substrate onto thethird optical compensation layer to serve alone as a layer included inthe polarizing plate with optical compensation layers, or may belaminated as a laminate with the substrate (conductive layer with asubstrate) on the third optical compensation layer. Typically, asdescribed above, the conductive layer and the substrate may beintroduced as a conductive layer with a substrate into the polarizingplate with optical compensation layers.

Any appropriate resin is given as a material forming the substrate. Theresin is preferably a resin excellent in transparency. Specific examplesthereof include a cyclic olefin-based, resin, a polycarbonate-based,resin, a cellulose-based resin, a polyester-based resin, and an acrylicresin.

It is preferred that the substrate be optically isotropic. Therefore,the conductive layer can be used as a conductive layer with an isotropicsubstrate in the polarizing plate with optical compensation layers. Amaterial forming the substrate that is optically isotropic (isotropicsubstrate) is, for example, a material using a resin free of anyconjugated system, such as a norbornene-based resin or an olefin-basedresin, as a main skeleton, or a material having a cyclic structure, suchas a lactone ring or a glutarimide ring, in the main chain of an acrylicresin. The use of any such material can suppress the expression of aretardation in association with the orientation of the molecular chainof the material at the time of the formation of the isotropic substrateto a low level.

The substrate has a thickness of preferably from 10 μm to 200 μm, morepreferably from 20 μm to 60 μm.

A-7. Others

Any appropriate pressure-sensitive adhesive layer or adhesive-layer isused in the lamination of the respective layers constituting thepolarizing plate with optical compensation layers of the presentinvention. The pressure-sensitive adhesive layer is typically formed ofan acrylic pressure-sensitive adhesive. The adhesive layer is typicallyformed of a polyvinyl alcohol-based adhesive.

A pressure-sensitive adhesive layer may be arranged on the third opticalcompensation layer 50 side of the polarizing plate 100 with opticalcompensation layers, though the layer is not shown. When thepressure-sensitive adhesive layer is arranged in advance, the polarizingplate with optical compensation layers can be easily bonded to any otheroptical member (e.g., an organic EL cell). A release film is preferablybonded to the surface of the pressure-sensitive adhesive layer until thepolarizing plate with optical compensation layers is used.

B. Organic EL Panel

An organic EL panel of the present invention includes an organic EL celland the polarizing plate with optical compensation layers described inthe section A on the viewer side of the organic EL cell. The polarizingplate with optical compensation layers is laminated so that the thirdoptical compensation layer may be on an organic EL cell side (thepolarizer may be on the viewer side).

EXAMPLES

Now, the present invention is specifically described by way of Examples.However, the present invention is not limited by these Examples.Measurement methods for characteristics are as described below.

(1) Thickness

Measurement was performed with a dial gauge (manufactured by PEACOCK,product name: “DG-205” , dial gauge stand (product name: “pds-2” )).

(2) Retardation

A sample measuring 50 mm by 50 mm was cut out of each opticalcompensation layer to provide a measurement sample, and its retardationvalues were measured with AxoScan manufactured by Axometrics, Inc.Measurement, wavelengths were 450 nm and 550 nm, and a measurementtemperature was 23° C.

In addition, the average refractive indices of the sample were measuredwith an Abbe refractometer manufactured by Atago Co., Ltd., and itsrefractive indices nx, ny, and nz were calculated from the resultantretardation values.

(3) Reflection Characteristic in Oblique Direction

A simulation was performed by using the characteristics of polarizingplates with optical compensation layers obtained in Examples andComparative Examples. Evaluations were performed for a front direction(polar angle: 0°) and an oblique direction (polar angle: 60°). “LCDMASTER Ver. 6.084” manufactured by Shintech, Inc. was used in thesimulation. The simulation of reflection characteristics was performedby using the extended function of the LCD Master. In more detail, afront reflection intensity, a front reflection hue, an obliquereflection intensity, and an oblique reflection hue were evaluated. Theoblique reflection intensity was evaluated in terms of the average ofvalues measured at a polar angle of 60° and four azimuth angles, thatis, 45°, 135°, 225° and 315°. The front reflection hue was evaluated interms of Δu′v′ (neutral) from a neutral point, and the obliquereflection hue was evaluated in terms of a color shift Δu′v′ at a polarangle of 60° and an azimuth angle of from 0° to 360°.

Example 1

(i) Production of First Optical Compensation Layer

(i-1) Synthesis of Polyarylate

27.0 kg of 2,2-bis(4-hydroxyphenyl)-4-methylpentane and 0.8 kg oftetrabutylammonium chloride were dissolved in 250 L of a sodiumhydroxide solution in a reaction vessel equipped with a stirringapparatus. To the stirred solution, a solution, obtained by dissolving13.5 kg of terephthaloyl chloride and 6.30 kg of isophthaloyl chloridein 300 L of toluene was added all at once, followed by stirring at roomtemperature for 90 minutes. Thus, a polycondensation solution wasobtained. After that, the polycondensation solution was separated bybeing left to stand still to separate a toluene solution containingpolyarylate. Next, the separated liquid was washed with aqueous aceticacid and further washed with ion-exchanged water. After that, the washedproduct was loaded into methanol to precipitate the polyarylate. Theprecipitated polyarylate was filtered and dried under reduced pressureto provide 34.1 kg of white polyarylate (yield: 92%). The birefringentindex (Δn_(xz)) of the polyarylate was 0.012.

(i-2) Production of Retardation Layer

An application liquid was prepared by dissolving 10 kg of thepolyarylate obtained in the foregoing in 73 kg of toluene. After that,the application liquid was directly applied onto a shrinkable film(longitudinally uniaxially stretched polypropylene film, manufactured byTokyo Printing Ink Mfg. Co., Ltd., product name: “NOBLEN” ), and theapplied film was dried at a drying temperature of 60° C. for 5 minutesand then at a drying temperature of 80° C. for 5 minutes to form alaminate of the shrinkable film and a birefringent layer. The resultantlaminate was stretched with a simultaneous biaxial stretching machine ata stretching temperature of 155° C. in its MD direction at a shrinkageratio of 0.70 and in its TD direction at 1.15 times. Thus, a retardationfilm was formed on the shrinkable film. Next, the retardation film waspeeled from the shrinkable film. The retardation film had a thickness of15.0 μm, an Re(550) of 272 nm, and an Nz coefficient of 0.25. Theretardation film was used as a first optical compensation layer.

(ii) Production of Second Optical Compensation Layer

An application liquid was prepared by dissolving 10 kg of thepolyarylate obtained in the (i-1) in 73 kg of toluene. After that, theapplication liquid was directly applied onto a shrinkable film(longitudinally uniaxially stretched polypropylene film, manufactured byTokyo Printing Ink Mfg. Co., Ltd., product name: “NOBLEN”), and theapplied film was dried at a drying temperature of 60° C. for 5 minutesand then at a drying temperature of 80 ° C. for 5 minutes to form alaminate of the shrinkable film and a birefringent layer. The resultantlaminate was stretched with a simultaneous biaxial stretching machine ata stretching temperature of 155° C. in its MD direction at a shrinkageratio of 0.80 and in its TD direction at 1.17 times. Thus, a retardationfilm was formed on the shrinkable film. Next, the retardation film waspeeled from the shrinkable film. The retardation film had a thickness of17 μm, an Re(550) of 240 nm, and an Nz coefficient of 0.50. Theretardation film was used as a second optical compensation layer.

(iii) Production of Third Optical Compensation Layer

An application liquid was prepared by dissolving 10 kg of thepolyarylate obtained in the (i-1) in 73 kg of toluene. After that, theapplication liquid was directly applied onto a shrinkable film(longitudinally uniaxially stretched polypropylene film, manufactured byTokyo Printing Ink Mfg. Co., Ltd., product name: “NOBLEN” ), and theapplied film, was dried at a drying temperature of 60° C. for 5 minutesand then at a drying temperature of 80° C. for 5 minutes to form alaminate of the shrinkable film and a birefringent layer. The resultantlaminate was stretched with a simultaneous biaxial stretching machine ata stretching temperature of 155° C. in its MD direction at a shrinkageratio of 0.81 and in its TD direction at 1.15 times. Thus, a retardationfilm was formed on the shrinkable film. Next, the retardation film waspeeled from the shrinkable film. The retardation film had a thickness of8 μm, an Re(550) of 120 nm, and an Nz coefficient of 0.50. Theretardation film was used as a third optical compensation layer.

(iv) Production of Polarizer

While an elongate roll of a polyvinyl alcohol (PVA)-based resin filmhaving a thickness of 30 μm (manufactured by Kuraray Co ., Ltd., productname: “PE3000” ) was uniaxially stretched with a roll stretching machinein its lengthwise direction so that a stretching ratio became 5.9 timesin the lengthwise direction, the roll was simultaneously subjected toswelling, dyeing, cross-linking, and washing treatments. Finally, theroll was subjected to drying treatment to produce a polarizer having athickness of 12 μm.

Specifically, in the swelling treatment, the roll was stretched at 2.2times while being treated with pure water at 20° C. Next, in the dyeingtreatment, the roll was stretched at 1.4 times while being treated in anaqueous solution at 30° C. in which a weight ratio between iodine andpotassium iodide was 1:7, the aqueous solution having an iodineconcentration adjusted so that the single layer transmittance of thepolarizer to be obtained became 45.0%. Further, two-stage cross-linkingtreatment was adopted as the cross-linking treatment, and in thefirst-stage cross-linking treatment, the roll was stretched at 1.2 timeswhile being treated in an aqueous solution at 40° C. obtained bydissolving boric acid and potassium iodide. The boric acid content andpotassium iodide content of the aqueous solution in the first-stagecross-linking treatment were set to 5.0 wt % and 3.0 wt %, respectively.In the second-stage cross-linking treatment, the roll was stretched at1.6 times while being treated in an aqueous solution at 65° C. obtainedby dissolving boric acid and potassium iodide. The boric acid contentand potassium iodide content of the aqueous solution in the second-stagecross-linking treatment were set to 4.3 wt % and 5.0 wt %, respectively.In addition, in the washing treatment, the roll was treated with anaqueous solution of potassium iodide at 20° C. The potassium iodidecontent of the aqueous solution in the washing treatment was set to 2.6wt %. Finally, in the drying treatment, the roll was dried at 70° C. for5 minutes to provide the polarizer.

(v) Production of Polarizing Plate

A HC-TAC film (thickness: 32 μm, corresponding to a protective layer)having a hard coat (HC) layer formed on one surface of a TAC film byhard coat treatment was bonded to one side of the polarizer via apolyvinyl alcohol-based adhesive by a roll-to-roll process. Thus, anelongate polarizing plate having the configuration “protectivelayer/polarizer” was obtained.

(vi) Production of Polarizing Plate with Optical Compensation layers

The polarizing plate, the first optical compensation layer, the secondoptical compensation layer, and the third optical compensation layerobtained in the foregoing were cut into predetermined sizes. Thepolarizer surface of the polarizing plate and the first opticalcompensation layer were bonded to each other via an acrylicpressure-sensitive adhesive, and the second optical compensation layerand the third optical compensation layer were bonded to the resultant inthe stated order via acrylic pressure-sensitive adhesives. Thus, apolarizing plate with optical compensation layers having theconfiguration “protective layer/polarizer/first optical compensationlayer/second optical compensation layer/third optical compensationlayer” was obtained. The cutting of the first optical compensation layerwas performed so that the absorption axis of the polarizer and the slowaxis of the first optical compensation layer were substantiallyperpendicular to each other in the polarizing plate with opticalcompensation layers. The cutting of the second optical compensationlayer was performed so that an angle formed by the absorption axis orthe polarizer and the slow axis of the second optical compensation layerbecame 75°. The cutting of the third optical compensation layer wasperformed so that an angle formed by the absorption axis of thepolarizer and the slow axis of the third optical compensation layer became 15°.

(vii) Production of Organic EL Panel

A pressure-sensitive adhesive layer was formed on the third opticalcompensation layer side of the resultant polarizing plate with opticalcompensation layers by using an acrylic pressure-sensitive adhesive.

A smartphone (Galaxy-S5) manufactured by Samsung Electronics Co., Ltd.was dismantled, and its organic EL panel was taken out. A polarizingfilm bonded to the organic EL panel was peeled off, and the polarizingplate with optical compensation layers cut out in the foregoing wasbonded instead to the remainder. Thus, an organic EL panel was obtained.

The simulation of reflection characteristics described in the (3) wasperformed by using the characteristics of the resultant polarizing platewith optical compensation layers. The results are shown in Table 1.

Example 2

A polarizing plate with optical compensation layers having theconfiguration “protective layer/polarizer/first optical compensationlayer/second optical compensation layer/third, optical compensationlayer” was obtained in the same manner as in Example 1 except that thelamination was performed so that the angle formed by the absorption axisof the polarizer and the slow axis of the second optical compensationlayer became 15°, and the angle formed by the absorption axis of thepolarizer and the slow axis of the third optical compensation layerbecame 75°. Further, an organic EL panel was produced in the same manneras in Example 1 except that the polarizing plate with opticalcompensation layers was used. The polarizing plate with opticalcompensation layers and the organic EL panel thus obtained weresubjected to the same evaluations as those of Example 1. The results areshown in Table 1.

Comparative Example 1

A polarizing plate with optical compensation layers having theconfiguration “protective layer/polarizer/second optical compensationlayer/third optical compensation layer” was obtained in the same manneras in Example 1 except that the first optical compensation layer was notlaminated. Further, an organic EL panel was produced in the same manneras in Example 1 except that the polarizing plate with opticalcompensation layers was used. The polarizing plate with opticalcompensation layers and the organic EL panel thus obtained weresubjected to the same evaluations as those of Example 1, The results areshown in Table 1.

Comparative Example 2

A polarizing plate with optical compensation layers having theconfiguration “protective layer/polarizer/first, optical compensationlayer/third optical compensation layer” was obtained in the same manneras in Example 1 except that the second optical compensation layer wasnot laminated. Further, an organic EL panel was produced in the samemanner as in Example 1 except that the polarizing plate with opticalcompensation layers was used. The polarizing plate with opticalcompensation layers and the organic EL panel thus obtained weresubjected to the same evaluations as those of Example 1. The results areshown in Table 1.

Comparative Example 3

A polarizing plate with optical compensation layers having theconfiguration “protective layer/polarizer/first optical compensationlayer/second optical compensation layer” was obtained in the same manneras in Example 1 except that, the third optical compensation layer wasnot laminated. Further, an organic EL panel was produced in the samemanner as in Example 1 except that the polarizing plate with opticalcompensation layers was used. The polarizing plate with opticalcompensation layers and the organic EL panel thus obtained weresubjected to the same evaluations as those of Example 1. The results areshown in Table 1.

TABLE 1 First optical compensation layer Absorption axis of Secondoptical compensation Third optical compensation polarizer layer layerand slow Re450/ Axis R450/ Axis Re Rth Nz axis Re Rth Nz Re550 angle ReRth Nz Re550 angle Example 1 270 68 0.25 Perpendicular 240 120 0.5 1.175 120 60 0.5 1.10 15 Example 2 270 68 0.25 Perpendicular 240 120 0.51.1 15 120 60 0.5 1.10 15 Comparative — — — — 240 120 0.5 1.1 75 120 600.5 1.10 15 Example 1 Comparative 270 68 0.25 Perpendicular — — — — —120 60 0.5 1.10 15 Example 2 Comparative 270 68 0.25 Perpendicular 240120 0.5 1.1 75 — — — — — Example 3 Simulation Front reflection ObliqueOrganic EL panel Front hue Oblique reflection Front Front ObliqueOblique reflection Δu′v′ reflection hue reflection reflection reflectionreflection intensity (neutral) intensity Δu′v′ intensity hue intensityhue Example 1 0.00021 0.21 0.00123 0.19 ∘ ∘ ∘ ∘ Example 2 0.00021 0.210.00135 0.22 ∘ ∘ ∘ ∘ Comparative 0.00021 0.22 0.01234 0.31 ∘ ∘ x ∘Example 1 Comparative 0.25691 0.033 0.22225 0.004 x ∘ x ∘ Example 2Comparative 0.33030 0.008 0.28877 0.029 x ∘ x ∘ Example 3

Evaluation

As is apparent from Table 1, the polarizing plate with opticalcompensation layers of each of Examples of the present invention isexcellent in both antireflection characteristic (reflection intensity)and reflection hue in each of the front direction and the obliquedirection.

INDUSTRIAL APPLICABILITY

The polarizing plate with optical compensation layers of the presentinvention is suitably used for an organic EL panel.

REFERENCE SIGNS LIST

-   10 polarizer-   20 protective layer-   30 first optical compensation layer-   40 second optical compensation layer-   50 third optical compensation layer-   100 polarizing plate with optical compensation layers

The invention claimed is:
 1. A polarizing plate with opticalcompensation layers, comprising: a polarizer; a first opticalcompensation layer; a second optical compensation layer; and a thirdoptical compensation layer, wherein each of the first opticalcompensation layer, the second optical compensation layer, and the thirdoptical compensation layer shows a refractive index characteristic ofnx>nz>ny, the polarizing plate with optical compensation layers is usedfor an organic EL panel, the second optical compensation layer has anRe(550) between 210 nm to 270 nm and an Nz coefficient between 0.3 to0.7, and an angle formed by an absorption axis of the polarizer and aslow axis of the second optical compensation layer is from 5° to 25°,from 65° to 85°, from 95° to 115°, or from 155° to 175°, and the firstoptical compensation layer has an Re(550) between 230 nm to 310 nm andan Nz coefficient between 0.1 to 0.4, and an absorption axis of thepolarizer and a slow axis of the first optical compensation layer aresubstantially perpendicular to each other.
 2. The polarizing plate withoptical compensation layers according to claim 1, wherein each of thefirst optical compensation layer, the second optical compensation layer,and the third optical compensation layer satisfies a relationship ofRe(450)≥Re(550) where Re(450) and Re(550) represent in-planeretardations measured at 23° C. with light having a wavelength of 450 nmand light having a wavelength of 550 nm, respectively.
 3. The polarizingplate with optical compensation layers according to claim 1, wherein thethird optical compensation layer has an Re(550) between 80 nm to 160 nmand an Nz coefficient between 0.3 to 0.7, and an angle formed by anabsorption axis of the polarizer and a slow axis of the third opticalcompensation layer is from 5° to 25°, from 65° to 85°, from 95° to 115°,or from 155° to 175°.
 4. An organic EL panel, comprising the polarizingplate with optical compensation layers of claim
 1. 5. The polarizingplate with optical compensation layers according to claim 1, wherein thefirst optical compensation layer has an Re(550) between 230 nm to 310 nmand an Nz coefficient between 0.6 to 0.9, and an absorption axis of thepolarizer and a slow axis of the first optical compensation layer aresubstantially parallel to each other.
 6. A polarizing plate with opticalcompensation layers, comprising: a polarizer; a first opticalcompensation layer; a second optical compensation layer; and a thirdoptical compensation layer, wherein each of the first opticalcompensation layer, the second optical compensation layer, and the thirdoptical compensation layer shows a refractive index characteristic ofnx>nz>ny, and satisfies a relationship of Re(450)≥Re(550) where Re(450)and Re(550) represent in-plane retardations measured at 23° C. withlight having a wavelength of 450 nm and light having a wavelength of 550nm, respectively, wherein the first optical compensation layer has anRe(550) between 230 nm to 310 nm and an Nz coefficient between 0.1 to0.4, and an absorption axis of the polarizer and a slow axis of thefirst optical compensation layer are substantially perpendicular to eachother, wherein the second optical compensation layer has an Re(550)between 210 nm to 270 nm and an Nz coefficient between 0.3 to 0.7, andan angle formed by an absorption axis of the polarizer and a slow axisof the second optical compensation layer is from 5° to 25°, from 65° to85°, from 95° to 115°, or from 155° to 175°, and wherein the thirdoptical compensation layer has an Re(550) between 80 nm to 160 nm and anNz coefficient between 0.3 to 0.7, and an angle formed by an absorptionaxis of the polarizer and a slow axis of the third optical compensationlayer is from 5° to 25°, from 65° to 85°, from 95° to 115°, or from 155°to 175°.
 7. An organic EL panel, comprising the polarizing plate withoptical compensation layers of claim
 6. 8. A polarizing plate withoptical compensation layers, comprising: a polarizer; a first opticalcompensation layer; a second optical compensation layer; and a thirdoptical compensation layer, wherein each of the first opticalcompensation layer, the second optical compensation layer, and the thirdoptical compensation layer shows a refractive index characteristic ofnx>nz>ny, and satisfies a relationship of Re(450)≥Re(550) where Re(450)and Re(550) represent in-plane retardations measured at 23° C. withlight having a wavelength of 450 nm and light having a wavelength of 550nm, respectively, wherein the first optical compensation layer has anRe(550) between 230 nm to 310 nm and an Nz coefficient between 0.6 to0.9, and an absorption axis of the polarizer and a slow axis of thefirst optical compensation layer are substantially parallel to eachother, wherein the second optical compensation layer has an Re(550)between 210 nm to 270 nm and an Nz coefficient between 0.3 to 0.7, andan angle formed by an absorption axis of the polarizer and a slow axisof the second optical compensation layer is from 5° to 25°, from 65° to85°, from 95° to 115°, or from 155° to 175°, and wherein the thirdoptical compensation layer has an Re(550) between 80 nm to 160 nm and anNz coefficient between 0.3 to 0.7, and an angle formed by an absorptionaxis of the polarizer and a slow axis of the third optical compensationlayer is from 5° to 25°, from 65° to 85°, from 95° to 115°, or from 155°to 175°.
 9. An organic EL panel, comprising the polarizing plate withoptical compensation layers of claim 8.